Polymers from allylic alcohol monoethers of trihydric alcohols



Patented Mar. 20, 1951 POLYMERS FROM ALLYLIC ALCOHOL MONOETHERS OF TRIHYDRIC AL- COHOLS Hans Dannenberg and David E. Adelson, Berkeley, Calif., assignors to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application January 3, 1948, Serial No. 470

15 Claims.

a This invention relates to polymer from allylic alcohol monoethers of trihydric alcohols and to a method of producing them. More particularly the invention provides a process for an economical polymerization of such ethers, and in its most specific embodiment provides poly(3-allyloxy- 1,2-propanediol), the polymer of the alpha-allyl monoether of glycerol, prepared by air. blowing the-monomer.

.1. It is known to polymerize the unsaturated alcohol polyethers of polyhydric alcohols. Such ethers contain a plurality of polymerizable groups and their polymerization is readily induced. The diallyl diether of glycerol, for example, polymerizes spontaneously merely upon standing. It is an inherent characteristic of such polyethers that their complete polymerization results in the formation of the three dimensional cross-linked polymers known as infusible polymers. Infusible polymers are characterized by their extreme insolubility in the vast majority of solvents and their resistance to melting or softening at temp'eratures below their decomposition temperature. Polymers prepared from the unsaturated alcohol polyethers of polyhydric alcohols therefore have a relatively limited applicationin the field of plastics. A typical use of such polymers embodies a careful incomplete polymerization of the monomer to a form still retaining the solubility characteristics of the fusible linear polymers, the

application of films of the incompletely polymerized material upon other plastic materials, and their subsequent infusibilization to provide a res istant surface coating. Polyhydric alcohols are this manner polymers are formed which have great value as anti-spattering agents and emulsifyingagents, but are of little utility in the field of plastics.

l Itis therefore an object of the. present invention to provide a process employing a particular class of unsaturated alcohol ethers of polyhydric alcohols in which a single allylic alkenyl radical replaces the hydrogen atom of one hydroxyl group of a trihydric alcohol, and producing valuable fusible linear polymers. Another object is the provision of a process for the production of 2 poly(3-allyloxy-1,2-propanediol) that is not dependent upon the employment of a catalyst or severe reaction conditions. A further object of the invention is the provision of a class of polymeric materials having molecular weights of 1000 or above, a linearstructure, and an average of a.

single unsaturated linkage per polymeric molecule.

description.

We have now found that heating the allylic alcohol monoethers of trihydric alcohols in the presence of polymerization catalysts containing an oxygenatom directly linked to another oxygen atom produces particularly valuable linear polymers. As employed throughout the specification and appended claims, the term allylic alcohol is employed in the sense that it is used by the writers of modern chemical texts, to mean the alcohols exhibiting unique chemical properties by virtue of the presence of a hydroxyl group and a non-conjugated olefinic double bond in the structural arrangement C=CCOH, and is herein limited to the class of such alcohols in which the remaining valences of the carbon atoms are satisfied by hydrogen atoms or saturated aliphatic hydrocarbon radicals.

The discovery that allylic alcohol monoethers of trihydric alcohols, particularly such ethers of glycerol, form linear polymers when heated in the presence of the catalysts more fully described below, many of which are known to be oxidizing agents, is surprising in view of the reactions which by analogy would be expected to result from such 'a treatment. Heating in the presence of gaseous oxygen is well known to be a general usually in the form of air. Glycerol is known to:

form mixtures of glyceraldehyde and dihydroxy acetone upon mild oxidation, and further oxidation products form a more strenuous oxidation. A similar reaction would be expected from an ether of glycerol in whichtwo hydroxyl groups remain unsubstituted and thus available for oxi-, dation. In addition, the double bond of the al-l lylic alcohols is known to be susceptible to oxidation as illustrated by the formation of glycerol from a reaction of allyl alcohol with an oxygen-' yielding oxidizing agent.

In the present process, however, these numerous oxidation reactions which would be expected to be the predominant reaction induced by the airblowing treatment occur but to a very limited Still other objects and advantages of theinvention will be apparent from the following extent. Surprisingly enough the reaction is substantially one of tarmac-carbon polymerization. As will be more fully illustrated by 'the detailed examples, the monomeric alkenyl ether of glycerol which has a high content of hydroxyl groups per unit weight, as well as a highcontent of unsaturated groups per unit weight converted to a poly(alkenyloxypropanediol) having substantially the same content of hydroxyl groups per unit weight but in which the content of unsaturated groups per unit weight have been reduced substantially in direct proportion to the number of molecules of the monomer combined in each molecule of polymer. Thus the poly merization predominately occurs by the addition of the carbon-to-carbon unsaturated linkages to form linear polymers, and the expected oxidation reactions to form complex mixtures in which the hyercxyrgropps have been converted to -mpre highly oxidized forms "does not occur, oi' talges place to only a very limited extent.

Allylic alcohol nionoethers bf triifydric"'a lctihc'ils ftir'ming suitable starting materials for the pres ent process may also be defined as -2-alkenyl di= hydroxyalkany-l others. 'Of such ether's it has been :found preferable to employ those which the -dihydroxyalka-riyl radical is a 2,3-dihyd'roxy propanyl radical, CH;CH(OH)CH2OH, and in which the 2-a'lkenyl radical contains a terminal methylene group C-H 2). "The preferred starti'ng materials are thus -2'-m'e'thylenealk anyl dilly"- cro yprdpyi *etl'iers and such'ethers'in which the 2 -inetliylidenealkanyl radical contains not more than about 6 carbon atoms produce particularly valuable polymers having high molecular weights, excellent solubility properties, and the prdper-ty of readily entering into reactions with unsaturated acids to form valuable coating'materials.

-Illustra-tive examples of 2-alkenyl dihydroxyalkanyl ethers include, -3-a-llylox:y--1,2-epropane'- diol, -2 allyloxy 1,3 propanediol, -2 methyl-2- propenyl, 2,3-dihydroxybutyl ether, crotyl 2, 3- dihydroxy-2-methylpropyl ether, Z-pentenyl 1.,1- dimethyl-2,3-dihydroxyprqpyl ether, 2 -methyl enepentyl,-2 ,3 or 1,-3-dihydroxypropyl ether, and 2- pentenyl 2,4-dihydroxybutyl ether. illustrative examples of 2;methyl enealkanyl dihydroxypropyl ethers include, 3-allyloxy-'1,2- propanediol, 2-m ethyl 2-propenyl 1,3- or 2,3-dih ydrox-ypropyl ether, 2-methyleneperityl 13- :01 2,3- dihydroxypropyl ether, Z-"methyIenebutyl 1,2- or;;2,3 dihydroxypropyl ether and 'I-methy'l-Q- methylenepropyl12,3-dihydroxypropyl ether.

-A wide range of reaction temperatures maybe employed in the execution of the process of "the invention, any temperature from about normal room temperature to the decomposition temperature of the 'alke'hylmonoether of glycerol employed being suitable. A generally preferred range of temperatures lies between '100 C. to 2 0C.

The process of the invention 'may be g'en'ermany defined as heating 'a 2-alk'eii'y1 'diliYdrdXyalkariyl ether in the presence of 'a'polymeri'zatid'n catalyst which contains an oxygen atom linked directly to another oxygen atom, and which initiates polymerization by forming compounds having anacid ionization cdnstant'of less than 0.4. A variety of substancesjar'e suitable for catalyzing the reaction including benz'o'yl peroxide, hydrogen "peroxide, barium peroxide, s'o'diuin peroxide, ithealk'ali 'metalperborate's and persulfates, tetr'alin peroxide, "o'l'efin "peroxide, acetyl peroxide, atetcn'e peroxide and "the like.

Of these eompounds benzoyl peroxide and by drogen peroxide are preferred catalysts. The catalysts aie'us'ed in amounts ranging from about 0.5 to 5.0 per cent of the ether being treated. If desired, of course, smaller or larger amounts of catalyst may be utilized. As the reaction proceeds, the catalyst may be consumed to a greater or lesser extent, and this may be obviated by addition of fresh catalyst to the reaction mixture to replace that which is destroyed o'rcons'umed. I

A particularly "preferred catalyst for use in the process is a gas containing molecular oxygen. Molecular oxygen may be used in a substantially pure form or may contain various diluent gases such as nitrogen, carbon dioxide, argon or other inert gases. Preferably the gas contains at least 10 per cent of molecular oxygen. Air is ordimanly well suited for effecting "the desired polycremation. t is "preferred that the compound employed as a catalyst have an appreciable son bili-ty in the ether subjected to polymerization, e. that the compound be at least as soluble at 25 C. as "the pxyg-en 'of air in the 'ether under a total pressure of "one atmosphere.

The process may be conducted in a variety of manners. In general, it is preferable to conduct tlie polymerization in a closed vessel equipped with a heating means. When a non-gaseous catalyst is employed, the catalyst is mixed with the ether and the mixture heated to elfect the polymerization. In cases where a :gaseous c'at alyst is used, the gas is dispensed through the heated liquid ether and preferably recycled. It is usually preferable to provide passage of the discharged gaseous catalyst through some r'ecovering means such as a condenser to remove the minor amounts of ether carried along vsiith the gaseous current.

While it is generally preferable to empio'y a pure 2 -alkenyl 'diliydroxfyalkanyl ether, in "certain cases it has been round desirable to empicy an inert solvent. Hydrocarbons are particularly suitable for "this purpose and examples of compounds include benzene, "toluene, heptane, hexane, naphtha the like.

The iih'eiiiical purity of the monomeric -ether has been -fb'un'd to be an important factor the color of the resulting polymer. Where clear liglit colored polymers are desired it is premiere to employ a 2-alk'en'y1 -dihyd'roxyalkaiiyl other which is substantially free "of halogen.

in polymeriz ng the others, the polymerization reaction is ordinarily stopped before an (if "the monomer has been conv'eit'ed to the pdlyme'r, thus alldwing an on; conyen'ient "removal or the monomer by distillation. in the present process the reaction products may in addition-be rcadiiy separated by selective :solva'tidn. The monomeric z-alkeriyl :dihydroxyalkanyl ether is in many cases sombr in solvents such as acetone, while thepdly(2-alkenyl"dihydroxyalkai'iyletlier) isiirsoluble "in solvents "of this ty'pe but is soluble ina s'dlyent such as isopropyl alcohol.

The novel linear polymers or the invention'are very valuable substances. "Ihey find application as plasticizers and softeners for various plastic materials in which an increased "solubility for ionic solvents of adv'a'nta'g'e. They have the general properties "of very high molecular "weight aliphatic 'polyhydric alcohols, and have a parti'cular valuable application as "intermediates in the {formation or "air trying surfac'e toatings, to which they are "converted by es'terific'ation with high molecular -"vsreiglit unsaturated acids.

Fer-the purpose or further illustrati'fig the vention, the following examples are givenare to be, in no way construed as limiting the invention to the reactants,- catalysts, or modes of operation recited therein.

Example L-Air-bz bmg aribo c. v

Monomeric 3-allyloxy-1,2-propanediol;having a refractive index of 7'LD20 1.4620 anda chlorine content of less than 0.02%was maintained at a temperature of 190C. in a glass vessel equipped with; a reflux condenser.- A stream offal-ew s introduced beneath the surface of the liquid through a sintered glass disk' for a; period of 7 hours. The refractive index rose to i f? 1.- 4,920 an increase of 0,030.0. correspondingjftw-a conversion to polymer as determined; from? graph of refractive index against polymer "con tent. The polymer was found to have a molecular weight of 1020 by an ebullioscopical determination in ethyl alcohol corresponding to an aver age of 7.7 monomer units in the polymer molecules. The theoretical hydroxyl value of r the momoner is 1.513 and the polymer was found to have a hydroxyl value of 1.3 1(5) equivalent per 100 grams corresponding to a retention of 89% of the hydroxyl groups unchanged. The monomeric ether was found to have an iodine number of 199.6 and the polymer to have one of 22.5,

- though it is to be understoodthat these exampleswhich is 8.8 times less than that of the monomer.

grams, an iodine number of 27.4, an acidity of 0.001(5) equivalent per 100 grams and a carbonyl value of 0.001(5) equivalent per 100 grams.

To illustrate the effect of the halogen content on the polymer, a sample of 3-allyloxy-1,2-propanediol having a chlorine content of 0.27% was polymerized for 7 hours in the same manner. The resulting polymer was of a dark amber color (Gardner color of 16).

Example II .-.-Air-catalyzed polymerization at 130 C.

Monomeric 3-allyloxy-1,2-propanediol was heated in a glass vessel at 150 C. while a slow stream of air was passed into the liquid for about 25 hours. The refractive index rose to 1.4888 corresponding to a 46% conversion to polymer. The monomer was extracted from the polymer by means of acetone in which the monomer was soluble and the polymer insoluble. The polymer was then dissolved in isopropyl alcohol, filtered and the solvent removed. The polymer'was analyzed as follows:

Calculated as Found (001112092 Per cent carbon 54. 9(5) 54. 54 Per cent hydrogen- 9. 2(9) 9.09 Per cent oxygen 7(6) 36. 37 Molecular weight 270=l=10 264 Eaa'mple'III. -L 1ir catalyzd polymerization a I 200 c- The reaction was conducted in the mannerde-" scribed in Example I except that a temperature of 200 C. was maintained. I118 hours the'reaction mixture had are'fractive index of n 1,4724

corresponding to a conversion to polymer of macr r v Example IV.'Orgam'c peroxide initiated polymerization T p 1 V L'Whn 2-methylenebutyl 2,3-dihydroxypropyl ether is heate'd'in a pressure resistant vessel in the. presence ,of 3% by weightof tertiary-butyl hydroperoxide is maintained for 24 hours at 200 c..;1a;r.csi 1 e; polymer containing, a plurality of hydroxyl groups is formed. 1 l

:-; Example. Vr-zmorganic peroxide. initiated polymerization When 2 methylene 3 methylbutyl 2,3 dihydroxypropyl ether is heated to 150 C. in the presence of 5% by weight of sodium perborate propanediol) which comprises heating 3-allyloxy- 1,2-propanediol as sole polymerizable compound to a temperature between C. to 250 C. in the presence of a polymerization catalyst which contains an oxygen atom directly attached to another oxygen atom.

4. A process for the polymerization of a 2- methylenealkanyl dihydroxypropyl ether which comprises heating the ether as sole polymerizable compound to a temperature between 100 C, to 250 C. while introducing oxygen.

5. A process for the polymerization of a 2- alkenyl dihydroxyalkanyl ether which comprises heating the ether as sole polymerizable compound to a'temperature between 100 C. to 250 C. while introducing oxygen.

6. A linear addition homopolymer of 3-allyloxy-1,2-propanediol.

7. A linear addition homopolymer of a 2- methylenealkanyl dihydroxypropyl ether.

8. A .linear addition homopolymer of a 2- alkenyl dihydroxyalkanyl ether.

9. A process for producing linear polymers by air-blowing which comprises air-blowing 3-allyloxy-1,2-propanediol as sole polymerizable compound at a reaction temperature of substantially C.

10. A process for producing linear polymers by air-blowing which comprises air-blowing a 2- methylenealkanyl dihydroxypropyl ether as sole polymerizable compound at a temperature between 100 C. and 250 C.

11. A process for producing linear polymers by air-blowing which comprises air-blowing a 2- alkenyl dihydroxyalkanyl ether as sole polymerizable compound at a temperature between 100 C. and 250 C.

12. A process for the polymerization of a i alkenyl dihydroxypropy-l ether which comprises heating the ether as sole polymerizable compound to a temperature between 100 C. to "250 "C. while introducing oxygen.

'13. A linear addition 'homopolymer of a 2-- alkeny'l dihydroxypropyl "ether.

14. A process for the "production of a linear polymer of a 2-methylenealkany1 dihydroxypro pyl ether which comprises heating said ether as sole polymerizable compound. at 100 C. to 250 C. in liquid phase in intimate admixture with a polymerization catalyst which contains an "oxygen atom linked directly to another oxygen atom.

15. vA process for the production of a "linear polymer of a 2-alken'yl dihydroxyalkanyl ether which comprises heating said ether as sole polymerizable compound to an elevated temperature which is ibelow the decompositien temperature Number REFERENCES 'C ITED The following references are of record in the file (if 1311-15 m I fit UNITED swa ms mm T's ismitn s. -i Feb. 22, 1949 7 OTHER "REFERENCE-S Nichols :et al.: New Bases for Coating anli Plastic ZCOm flbs'itidfif article in Ofiii'al i-Dig s t, pages11 1-i1-23, March {945. 

8. A LINEAR ADDITION HOMOPOLYMER OF A 2ALKENYL DIHYDROXYALKANYL ETHER. 